1. Field of the Invention
The invention relates to a bicycle, more particularly to a bicycle frame having attachment means for quickly and easily mounting a rear carrier on a seat tube.
2. Description of the Related Art
For mounting a carrier rack on a bicycle frame, various forms of attachment devices have been suggested in the art. Some of them are available for mounting a front carrier to the bicycle frame above a front wheel, while others are used to attach a rear carrier to the bicycle frame above a rear wheel. FIG. 1 shows a conventional carrier rack 1xe2x80x2 which is supported on an axle of a rear wheel 3xe2x80x2 via upwardly extending frame members 11xe2x80x2 while being also attached, via a screw connection 5xe2x80x2 to a bicycle frame close to a location where a seat tube 2xe2x80x2 and a crossbar 4xe2x80x2 are joined together. Assembly of the carrier rack 1xe2x80x2 involves a time-consuming task.
U.S. Pat. No. 5,649,657 discloses a carrier assembly including a tubular support member to carry a carrier rack. The tubular support member has a front end incorporating a C-shaped clamp and clamping screws which lock the clamp tightly against a seat post above the juncture of a seat tube and a crossbar of a bicycle frame. This carrier assembly requires a screwing operation for attachment of the carrier rack to the bicycle frame.
U.S. Pat. No. 5,931,361 discloses a rear carrier mountable quickly and easily on a bicycle via a quickly releasable engaging clip which can be operated between clamping and non-clamping positions through a manually operable lever. This engaging clip embraces a seat post at a location above a connection between the seat post and a crossbar, where accidental downward sliding of the engaging clip member is possible if the clip member is not sufficiently tightened.
It is known to use mortise and tenon engagement components for attachment of accessory parts to a bicycle. U.S. Pat. No. 535,385 discloses a front carrier mounted on a front post of a bicycle frame. The carrier has an attachment plate with a tenon-like projection, whereas the front post is embraced by a collar or clip band which has a pair of projecting jaws defining a mortise groove therebetween for engagement with the attachment plate of the carrier. In that arrangement, the carrier is attached to the front post by clamping the collar or clip band tightly against the front post with a clamping screw and by subsequently engaging the mortise groove with the attachment plate of the carrier. U.S. Pat. No. 5,386,961 discloses a mounting unit attached to a seat post of a bicycle frame for mounting a bicycle lock on the frame. The mounting unit includes a C-shaped clamp member to embrace tightly the seat tube by means of screws. A tubular member for holding the bicycle lock is interlockable with the clamp member by means of a mortise-tenon engagement unit.
As mentioned above, the mortise-tenon engagement parts as suggested in the prior arts are designed to mount accessories other than a rear carrier. Although those mortise-tenon engagement parts can provide an advantage of quickly and easily assembling component parts, they have to cooperate with an embracing member to sleeve around a seat or front tube and a clamp mechanism to clamp tightly the embracing member against the tube. Downward sliding of the embracing member due to heavy load may occur in case of insufficient tightening action of the clamping mechanism. It is desirable that such mortise-and-tenon engagement parts can be used to mount a rear carrier on a bicycle frame without using a clamp mechanism.
An object of the present invention is to provide a bicycle frame with a rear carrier assembly which can be mounted on the bicycle frame in a quick and easy manner with the least possible number of mounting components for assembly.
Another object of the present invention is to provide a bicycle frame having a first engagement part integrally connected to a structural connection part between a seat post and a crossbar without using a clamp mechanism, and a second engagement part interlockable with the first engagement part and connected integrally to a rack.
A further object of the present invention is to provide a bicycle frame with a rear carrier which has a rack support rod connected integrally to a mortise or tenon engagement part for quick mounting of the carrier to the bicycle frame.
According to the present invention, a bicycle comprises: a frame including a seat tube, a crossbar extending forwardly of the seat tube, and a tubular connection part connected to and projecting upward from a rear end of the crossbar and sleeved around the seat tube, the seat tube extending upward from the tubular connection part, the tubular connection part having an integral first engagement block projecting rearwardly therefrom; a rack support rod having a front end with a front end face extending in a plane transverse to the rack support rod, a rear support portion extending rearwardly of the front end, and a second engagement block connected integrally to the front end, the second engagement block having a rear connecting face abutting with and connected integrally to the front end face, and an opposite front engagement face to interlock with the first engagement block, the rear connecting face and the front engagement face extending along a direction substantially parallel to the plane of the front end face; a rack member disposed above and fixed to the rear support portion; and mortise-tenon engagement means formed in the first engagement block and the front engagement face for releaseably interlocking the first and second engagement blocks, the mortise-tenon engagement means including a mortise member formed in one of the first engagement block and the front engagement face, and a tenon formed on the other one of the first engagement block and the front engagement face, the second engagement block being slidable relative to the first engagement block along a line substantially parallel to the plane of the front end face.